The collapse of the Hyatt-Regency walkway in Kansas City Missouri is widely regarded as the second deadliest structural collapse in the U.S history. This disaster is also known as the structural failure that single-handedly contributed many lessons to the study of engineering ethics of today.
In this post, we’ll take a brief look at one of the most significant events in the construction industry of the 20th century. This event was a turning point in terms of industry awareness of the critical role of the shop drawing process.
The Hyatt-Regency, Kansas city hotel in Missouri was a 40 storey building which began construction in the late 1970s. It was a significant landmark on the city skyline at the time. Prior to its completion, there were numerous delays and setbacks during the construction of the building. Including the dramatic collapse of the roof of the atrium at the north side of the building. Luckily this happened during a weekend, and nobody was injured. The hotel was, however, oﬃcially opened for operations on 1 July 1980.
Its lobby was one of the most interesting features of the building. Two suspended walkways spanned the atrium in the Hyatt Regency, with a second-floor walkway directly below a fourth-floor walkway. The walkways were approximately 120 ft (37 m) long and weighed approximately 29 tonnes.
Fast forward to 17 July 1981 when approximately 1600 people gathered in the atrium for a tea dance. The second floor held approximately 40 persons with more on the fourth-floor walkway. At approximately 7 pm that day, guests heard popping noises moments before the fourth-floor walkway fell into the second-floor walkway. Both walkway then fell to the ground killing 114 and severely injuring over 200 persons.
The investigation into the Failure
An architectural engineer was immediately hired to investigate the cause of the collapse. Apparently, a design flaw was discovered and was found responsible for the collapse. The original design required for the two suspended walkways to be suspended by a single set of hanger rods threaded through the upper walkway box beams and terminating beneath the box beams of the lower walkway (see figure 1).
The steel fabricator decided to change the design to a double rod system having discovered the initial design to be impracticable. One hanger rod connecting the ceiling to the upper walkway and the other connecting the lower and upper walkways. This change had the effect of doubling the load on the upper walkway connections (see figure two) resulting in a design capable of withstanding only an estimated 30 per cent of the mandated minimum.
A better way to illustrate this is to imagine you and a friend standing on a rope. The original design is the equivalent of you and your friend holding on to the rope independently. Whereas the design change is the equivalence of you holding onto the rope and your friend holding onto your waist. In both cases, the load on the rope is the same but the likelihood of your friend maintaining a firm grip is an issue.
In fact, another source of concern was that the original design wasn’t even adequate in the first place. According to Kansas building codes, the walkways only supported 60% of the minimum load required. Hence there was a fundamental problem of under-sized members.
Findings of the Investigation
The investigation concluded that the underlying problem was as a result of miscommunication between the designer and the steel fabricators. When the fabricators found that design to be impracticable, they requested approval for the double-rod system by telephone. The structural engineer gave the approval understanding that a written request for the change would be submitted for formal approval. However, the follow-up request was never honoured.
It is even on record that the steel fabricator subcontracted the work to an outside detailer due to increased workload. The outside detailer also under the belief that the double rod connection had been designed never carried out any calculations on the connections himself.
The design documents were later submitted to the approval engineer with a request for expedited approval. He assigned a review to be conducted by a technician. However, the connections were not detailed on the drawings and the technician did not perform any calculations on the connections. Also, the structural engineer only conducted spot checks on some portion of the drawing before the approval engineer aﬃxed his seal on the documents.
The design flaw was so obvious that any first-year engineering student could’ve figured it out. If only it had been checked
Jack D. Gillian
Aftermath of the Collapse
We cannot overstate it. The aftermath of any structural collapse is always tragic for all parties involved. According to reports virtually half of the residents of the town were affected directly or indirectly by the tragedy.
The structural engineers involved were found to be culpable of gross negligence, misconduct and unprofessional conduct in the practice of engineering. Although they were all acquited of all charges, however, they all lost all licenses as well as their membership with ASCE.
Months, after this tragedy not less than 300 lawsuits followed which sought a cumulative of 3billion dollars in damages of this only 140million dollars were awarded to the victims and their families.
If you agree that the underlying problem was as a result of miscommunication, then you wouldn’t be wrong. However, the biggest issue here has to do with engineering ethics.
The biggest ethical issue is that of the safety of the public. The people involved did not consider their actions to be endangering the health, safety and welfare of the public. Had this been taking into consideration, no loss of lives would’ve occurred. The engineers would not have lost their licenses or membership. Also, the firm wouldn’t have had its certificate of authority revoked nor would they have been any trial, talk more of multimillion-dollar settlement.
Another ethical issue that cannot be overlooked was that the original design wasn’t even adequate in the first instance. This could lead one to the assumption that the competency required to complete the structure was not even there. At the very least we could assume that the engineers might not have been familiar with the Kansas City Building code. However, the consequences of this lack of knowledge were injury and death of innocent lives, loss of licenses est.
To conclude, all parties involved had ethical questions to answer. From the steel fabricator, outside detailer, the technician to the structural engineer and the approval engineer. They could’ve performed independent calculations but instead, at every level, they all relied on someone’s else’s calculations. The sad thing, however, was that no calculations whatsoever was made. But they all had a moral obligation to put the public safety first.
There are many lessons to be learnt from this failure. But if one thing can be learnt from this failure, it would be never to rely on someone else to do the right thing. Every stage of a construction project is virtually important and has a significant effect on the safety of the overall project. From procurement to prefabrication and construction, negligence at any project stage can have dire consequences. This disaster was a question of engineering ethics and has been consistently used as a perfect example for students in STEM subjects around the globe.
Also see: The Hartford Civic Centre Roof Collapse
Marshal, Richard D; et al. (May 1982). Investigation of the Kansas City Hyatt Regency Walkways Collapse . Building Science Series. 143. U.S. Dept. of Commerce, National Bureau of Standards. Retrieved February 17, 2018.
Hyatt Regency walkway collapse– Wikipedia 2018
The Hyatt Regency Walkway Collapse (2007). The American Society of Civil Engineers. Retrieved from ASCE.org
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